You are correct. Should be noted that using all fissile material is not the same thing as ending up with zero radioactive waste. Not all material is fissile....

But ending up with over 1000x less, and having even what remains be far less dangerous than the status quo? Not to mention a huge source of hydrogen for a future hydrogen economy? Yeah, that's all true of Mark IV reactors. But we can't do it due to safety/environmental regs??? Ok, we'll keep our old, grandfathered plants running. Brilliant!!!

Of course, even our old plants still are far better (safer + cleaner) than any other known source of energy.

Less than 0.01% of nuclear waste is stored in pools. But it is the high grade stuff that is. And this is the material that is perfectly good fuel, could be used as such, with ALL of the resulting "waste" being far less dangerous. i.e. we took it out of the reactor before it was "done", so it's still reacting. We simply choose not to use it, not for commercial or technical reasons, but for geopolitical ones.

The water is more for heat than it is for radiation. Underwater, they are placed in a honeycomb structure of, typically, boronated stainless steel which attenuates thermal neutrons, and prevents the reaction from reaching criticality. The water does absorb some of the lower energy radiations, but it's mostly about keeping them cool. After a number of years, when the reaction slows enough, they can be removed from the pools and stored in dry casks, again made of boronated stainless.

The reason we don't recycle our fuel further is fair enough, and the only valid reason against nuclear. Proliferation. We take it out of the reactor prior to any weapons grade material being created. During the cold war (Carter admin), we made the call not to do this on the commercial level. Thus all weapons grade material is made only at national labs and can be controlled more closely. It's also a bad example for rogue countries like Iran, who CLAIM to want nuclear for peaceful purposes only. An attempt to separate power production from weapons production, in the idea that they can do one without being able to do the other.

The main premise of that article is the radiation from the coal ash escapes into the atmosphere or leaches into the soil or water. Not that the ash itself is more radioactive than the spent fuel from a nuclear reactor.

To be fair, the article doesn't say that coal ash is more radioactive than spent nuclear fuel rods (the small proportion of waste that is stored underwater). It says that a person living near a coal plant recieves more radiation than a person living near a nuclear plant, which is true.

Yes, on the whole coal plants do produce more radiation than nuclear plants. On a per MW basis, far more. However, even in fly ash (which is concentrated compared to coal), that radiation is spread over a much larger volume. i.e. far higher volume of slightly radioactive stuff vs. very low volume of highly radioactive stuff from nuclear.

Yeah, the water is for temperature reasons. But the temperature issue lies in the fact that the fuel rods are still "hot", and not just thermally. They are still undergoing fission, which produces the heat. Water merely provides a poor barrier to thermal neutrons. So the rods themselves are housed in nuetron attenuating steels, which slow the neutrons. And heavy water is a fairly effective shield against slower neutrons.

Again, the whole concept of having ANY waste that is hot enough that it is dangerous to handle and has to be stored underwater is purely by CHOICE. France, for instance, uses a much higher % of nuclear than we do and doesn't have this issue. They call our waste "fuel".